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Finding the Fourth Proportional to 398.80, 550.38 and 221.80

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Solution

The fourth proportional to 398.80, 550.38 and 221.80 is: 306.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    398.80 : 550.38 = 221.80 : x
  2. Step 2: Convert to fraction form
    398.80/550.38 = 221.80/x
  3. Step 3: Cross multiply
    398.80x = 550.38 × 221.80
  4. Step 4: Simplify right side
    398.80x = 122,072.29
  5. Step 5: Solve for x
    x = 122,072.29/398.80
  6. Step 6: Final answer
    x = 306.10

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.